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Oral Bioaccessibility of Nickel in Various Particle Sizes of House Dust from Communities Close to Nickel Mining and Smelting Operations

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Title: Oral Bioaccessibility of Nickel in Various Particle Sizes of House Dust from Communities Close to Nickel Mining and Smelting Operations
Author: Dai, Nancy
Department: School of Environmental Sciences
Program: Toxicology
Advisor: Hale, Beverley
Abstract: Particle size is known to influence leaching of Ni from soil and dust particles for total [Ni] and bioaccessibility. Little research has been done on Canadian dusts that contain Ni from mining and smelting sources, which may differ in speciation from that in the current literature. This work extends knowledge to a different set of samples. The relationship between particle size and oral nickel bioaccessibility was examined in pooled house dust previously studied in the Sudbury Soils Study. Dusts were separated into ranges of <10 µm, 10-41 µm, 41-70 µm, 70-105 µm, and 105-250 µm diameter fractions. Total [Ni] was determined following a modified reverse aqua regia acid digestion assay. Bioaccessibility was determined following the SBRC method. Both total and bioaccessible [Ni] increased inversely with particle size, though the relationship varied based on the dust group. Particle size and total [Ni] together explained much more of the variance in bioaccessible [Ni]. Bioaccessibility percentages were adjusted for their relative mass in each particle size range. Particles <10 µm and between 41 and 70 µm had high Ni bioaccessibility, and particles <10 µm and between 70 and 105 µm were highest after weight adjustment. Study results support that a more appropriate particle size for risk assessment use may be smaller than 250 µm. An upper limit of 105 µm is recommended.
URI: http://hdl.handle.net/10214/10125
Date: 2016-12


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